Anthropological field research by the Principal Investigator between 1964 and 1972 among some dozen villages of the Yanomamo Indians of the Venezuelan/Brazilian border revealed significant variability in that tribe in: (1) Village size, (2) frequencies of particular kinds of consanguineal marriages, (3) mortality by region due to warfare, (4) population growth-rate by region, (5) completed fertility among both males and females, (6) patterns of political leadership, (7) economic emphases according to micro-ecological adaptations and (8) processes of fissioning and redistribution of population segments into new, often hostile, villages. It was predicted at the beginning of the project in 1974 that the same kinds of variations would be found among other, previously un-studied groups of Yanomamo and that strong correlations would be found among the ecological, demographic and socio-political variables. Field research in four new areas of the tribes by four different researchers began in 1975 to address these issues and continued through the Summer of 1976. The new data includes detailed studies on approximately 30 Yanomamo villages found in widely separated regions and, as the analysis begins, reveals the predicted variations. The analysis will continue through 1976 and 1977.